1. Field of the Invention
The present invention relates to an auto-process camera, and more particularly to means for processing film units in an auto-process camera.
2. Description of the Prior Art
There is known a photographic process, which is frequently referred to as auto-process, and according to which film is provided in the form of individual units, each of which units comprises at least a negative image layer exposable to produce a negative or latent image of an object, and a positive image layer on which a positive, viewable image corresponding to the image produced on the negative image layer may be formed under the influence of a developing and processing solution which is diffused through the film unit, it being also possible for film units to contain other layers, depending on film unit type and purpose. It is usual practice to provide processing solution in breakable pods which are embedded in the film unit structure near one end portion thereof, and to provide, in an associated camera, pressure means, which are suitably constituted by a pair of rolls, for breaking open the pods. After being loaded into a camera and exposed, a film unit is moved, with the film unit end containing the processing solution pods foremost, and brought into engagement with and drawn through pressure rolls, which break open the pod and cause extrusion of the processing solution and diffusion thereof through the film unit, the film unit being brought immediately afterwards to the exterior of the camera, there thus being made available a viewable print a very short time after exposure of the film unit, without making it necessary for a photographer to proceed to a separate, specially equipped location for development and processing of film. The film unit may be drawn through the processing rolls either by means of a leader, which is constituted by a strip of paper or similar material, and is attached at one end to the film unit and may be pulled manually, or by means of actuation of one or both the processing rolls by mechanical or electrical drive means provided in the associated camera. In the latter case means are provided in the camera to forward the exposed film unit from an exposure station to, and into engagement with the processing rolls, and the processing rolls also act to forward the film unit out of the camera, which offers the advantage, for the photographer, of ease of manipulation. In either case, it is essential that the pressure exerted by the processing rolls be sufficient to ensure efficient spreading of processing solution through the film unit, but at the same time it must be possible for the film unit to be fed smoothly into engagement with the rolls without risk of jamming or damage to the film unit, which is a comparatively weak element. In conventional means these two conditions are difficult to meet, since the leading end portion of a film unit is generally slightly thicker than the rest of the film unit because it must accommodate processing solution pods, and processing rolls are normally urged into contact with one another by spring means and must be forced apart slightly by a film unit being moved out of the camera. Thus, if the force of the spring means for urging the rolls together is such as to cause the rolls to apply optimum pressure for spreading solution through the main portion of the film unit, it is difficult to guarantee smooth feed-in of the leading edge portion of a film unit into engagement with the rolls. On the other hand, if the force of the spring means is made less so that smooth feed-in of a film unit between the rolls is always guaranteed, the pressure exerted by the rolls is liable to be insufficient to guarantee complete diffusion of processing solution through all parts of the film unit, thus resulting in incompletely developed portions and unsatisfactory photographs.
Accordingly, an essential object of the present invention is to provide a film processing means for use in an auto-process camera which always permits unhindered engagement of successive exposed film units with pressure means, while also ensuring efficient diffusion of processing solution through the film units with substantial elimination of the disadvantages inherent in the conventional film processing means.
Another important object of the present invention is to provide a film processing means of the above described type which is accurate and stable in functioning.
A further object of the present invention is to provide a film processing means of the above described type which is simple in construction and can be manufactured at low cost for incorporation into an auto-process camera.